The invention relates to a method as well as an apparatus for the contactless determination of the quality of a test object in the category of meat products, particularly of a butchered animal carcass, parts thereof, or of a product derived essentially therefrom.
Methods and devices for the determination of the condition of foodstuffs are known, for example for the determination of the condition of freshness of fish, in which the ratio of the electric resistances of a fish is determined for two different measuring frequencies, for example.
Another method which works according to a similar physical principle has become known through the German Laid Open Specification No. 2,007,964, which states the conditions for dependence between the fresh condition of foodstuffs and their electrical characteristics, or between the fresh condition and a combination of different electrical characteristics of the corresponding foodstuff, respectively.
Foodstuffs considered here are fish, meat, poultry, vegetables, fruits as well as a number of other foodstuffs as long as they have a cell structure, such as milk and eggs. In addition, liquid foodstuffs, such as, for example, alcoholic beverages, are also considered.
In the known method, the test object is superficially maually scanned with a probe head which is equipped with circularly shaped electrodes arranged concentrically within one another. The relative dielectric constant or the specific resistance of the probe is measured. With the device, the object is to maintain quality-control of foodstuffs, for example, for the determination of the fresh condition, inexpensively and rapidly yet without carrying out the extraction of a sample.
Furthermore, different other methods and apparatus have become known for the determination of the weight by volume of meat wares and/or for the determination of their fat content. (for example Laid Out Specification No. 1,598 and Laid Out Specification No. 1,937,573.)
In these known methods and apparatus, after extraction of a sample, for example in the case of meat and sausage products, the sample is compressed a predetermined amount, the volume measured, the sample weighed, and through comparison of weight and volume, its fat content determined.
Such known testing methods and apparatus have in common the disadvantage that they can only be carried out by intimate contact with the test object or parts of the same, or with the extraction of a sample from foodstuffs, it is absolutely essential that the sample be discarded after the test.
By the utilization of probes which, for example, must be brought into definite electrical contact with the surface of the test object, or by puncturing with needles into the depth of the object, it is regarded as a particular disadvantage that on the one hand such apparatus or apparatus parts must be carefully cleaned after each use, and on the other hand, the contact betwween probe and test object creates an uncertainty factor which, even with the greatest care, cannot reliably be brought under control. Therefore, the result is not free from errors and risks, and supplies at best individual values at points and therefore still inaccurate individual values because of their dependence upon manipulation.
Unfortunately, in the case of foodstuffs, in spite of the existence of definitions as to the classification of goods, the classification into the different classes of goods is handled individually and therefore differently by experts, and with subjective judgment having wide dimensions of discretion. This results in economic loss.